Andersson, PontusNilsson, JimAkenine-Möller, TomasOskarsson, MagnusÅström, KalleFairchild, Mark D.Yuksel, Cem and Membarth, Richard and Zordan, Victor2020-10-302020-10-3020202577-6193https://doi.org/10.1145/3406183https://diglib.eg.org:443/handle/10.1145/3406183Image quality measures are becoming increasingly important in the field of computer graphics. For example, there is currently a major focus on generating photorealistic images in real time by combining path tracing with denoising, for which such quality assessment is integral. We present FLIP, which is a difference evaluator with a particular focus on the differences between rendered images and corresponding ground truths. Our algorithm produces a map that approximates the difference perceived by humans when alternating between two images. FLIP is a combination of modified existing building blocks, and the net result is surprisingly powerful. We have compared our work against a wide range of existing image difference algorithms and we have visually inspected over a thousand image pairs that were either retrieved from image databases or generated in-house. We also present results of a user study which indicate that our method performs substantially better, on average, than the other algorithms. To facilitate the use of FLIP, we provide source code in C++, MATLAB, NumPy/SciPy, and PyTorch.Computing methodologiesImage processingRendering.image differenceimage metric10.1145/3406183